output problem in file

i am trying to copy data from one file to another using fread & fwrite.the problem is the number of bytes to be read in the argument of fread & fwrite, which is the 2nd one.
fread (buffer,number of bytes,numbers of objects,FILE fp); this is my code-

#include<stdio.h>
#include<stdlib.h>

int main()
{ 
    FILE *fp, *fp1;
    char *p;
    fp=fopen ("a.txt","rb");
    fp1=fopen ("b.txt","wb");
    while (1) 
    {
        fread (p,sizeof(p),1,fp);
        if (feof (fp)) break;
        printf (p); 
        fwrite (p,sizeof(p),1,fp1);
    }

fclose (fp);
fclose (fp1);

}

the problem is with fread. if i specify 1/2 bytes, the output is exactly the same. if i use 4 bytes, which is the size of *p,according to my compiler, the sample output is-
input: christiano ronaldo
output: chri stia no r onal
it writes 4 characters, then some spaces are written. why’s that?

Is your *p initialized ? Use this

char *p = (char*)malloc( BUFFSIZE * sizeof(char) ); // and define BUFFSIZE as you want
//